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Inversely estimating the vertical profile of the soil CO2 production rate in a deciduous broadleaf forest using a particle filtering method.

Sakurai G, Yonemura S, Kishimoto-Mo AW, Murayama S, Ohtsuka T, Yokozawa M - PLoS ONE (2015)

Bottom Line: Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well.We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site.Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the "actual" values by decreasing the variance of the posterior distribution of the values.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki, Japan.

ABSTRACT
Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive manner. In this study, we estimated the temporal variation in the vertical profile of the CO2 production rate using a data assimilation method, the particle filtering method, in which the diffusion coefficients of CO2 were simultaneously estimated. The CO2 concentrations at several soil depths and CO2 efflux from the soil surface (only during the snow-free period) were measured at two points in a broadleaf forest in Japan, and the data were assimilated into a simple model including a diffusion equation. We found that there were large variations in the pattern of the vertical profile of the CO2 production rate between experiment sites: the peak CO2 production rate was at soil depths around 10 cm during the snow-free period at one site, but the peak was at the soil surface at the other site. Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well. We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site. Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the "actual" values by decreasing the variance of the posterior distribution of the values.

No MeSH data available.


Observed and estimated CO2 concentration at 5 depths at point A.The red lines and black lines show observed and estimated CO2 concentrations, respectively, at 0, 5, 10, 20, and 50 cm soil depths from 2005 to 2007 at point A. The estimated values were the average of 10,000 particles for each time step.
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pone.0119001.g001: Observed and estimated CO2 concentration at 5 depths at point A.The red lines and black lines show observed and estimated CO2 concentrations, respectively, at 0, 5, 10, 20, and 50 cm soil depths from 2005 to 2007 at point A. The estimated values were the average of 10,000 particles for each time step.

Mentions: The estimated soil CO2 concentrations replicated well the observed CO2 concentrations for all soil depths. Fig. 1 shows the observed and estimated temporal changes in CO2 concentrations at the five soil depths of point A. The root-mean-square errors (RMSE) between the observed and estimated CO2 concentrations were 0.017, 0.009, 0.018, 0.011, and 0.009 mol m–3 for 0, 5, 10, 20, and 50 cm soil depths, respectively, for point A and 0.017, 0.028, 0.015, and 0.022 mol m–3 for 0, 5, 10, and 20 cm soil depths, respectively, for point B.


Inversely estimating the vertical profile of the soil CO2 production rate in a deciduous broadleaf forest using a particle filtering method.

Sakurai G, Yonemura S, Kishimoto-Mo AW, Murayama S, Ohtsuka T, Yokozawa M - PLoS ONE (2015)

Observed and estimated CO2 concentration at 5 depths at point A.The red lines and black lines show observed and estimated CO2 concentrations, respectively, at 0, 5, 10, 20, and 50 cm soil depths from 2005 to 2007 at point A. The estimated values were the average of 10,000 particles for each time step.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4368638&req=5

pone.0119001.g001: Observed and estimated CO2 concentration at 5 depths at point A.The red lines and black lines show observed and estimated CO2 concentrations, respectively, at 0, 5, 10, 20, and 50 cm soil depths from 2005 to 2007 at point A. The estimated values were the average of 10,000 particles for each time step.
Mentions: The estimated soil CO2 concentrations replicated well the observed CO2 concentrations for all soil depths. Fig. 1 shows the observed and estimated temporal changes in CO2 concentrations at the five soil depths of point A. The root-mean-square errors (RMSE) between the observed and estimated CO2 concentrations were 0.017, 0.009, 0.018, 0.011, and 0.009 mol m–3 for 0, 5, 10, 20, and 50 cm soil depths, respectively, for point A and 0.017, 0.028, 0.015, and 0.022 mol m–3 for 0, 5, 10, and 20 cm soil depths, respectively, for point B.

Bottom Line: Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well.We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site.Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the "actual" values by decreasing the variance of the posterior distribution of the values.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki, Japan.

ABSTRACT
Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive manner. In this study, we estimated the temporal variation in the vertical profile of the CO2 production rate using a data assimilation method, the particle filtering method, in which the diffusion coefficients of CO2 were simultaneously estimated. The CO2 concentrations at several soil depths and CO2 efflux from the soil surface (only during the snow-free period) were measured at two points in a broadleaf forest in Japan, and the data were assimilated into a simple model including a diffusion equation. We found that there were large variations in the pattern of the vertical profile of the CO2 production rate between experiment sites: the peak CO2 production rate was at soil depths around 10 cm during the snow-free period at one site, but the peak was at the soil surface at the other site. Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well. We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site. Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the "actual" values by decreasing the variance of the posterior distribution of the values.

No MeSH data available.